Hydrogen peroxide is an important intermediate chemical useful in such applications as water treatment, pulp and paper bleaching, and organic synthesis. At present, the commercial process for producing hydrogen peroxide involves anthraquinone autooxidation (see, e.g., U.S. Pat. Nos. 4,428,923 and 6,524,547). The process requires numerous reaction and purification sections and uses a large amount of solvent. It is desirable for the chemical industry to develop more economical processes to produce hydrogen peroxide.
Hydrogen peroxide can be made by a direct reaction of hydrogen and oxygen in the presence of a catalyst. Considerable efforts have been devoted to develop a low-cost process to make hydrogen peroxide by the direct reaction. See, e.g., U.S. Pat. Nos. 6,168,775, 6,649,140, 5,846,898, 6,284,213, and 7,105,142. So far a commercially viable direct process is not yet available.
Sulfur compounds usually inhibit noble-metal-catalyzed reactions. See, e.g., Catal. Lett. 12 (1992) 287; Appl. Catal., B. 3 (1994) 205. For example, it has been reported that a thiol inhibits the hydrogenation activities of Pt or Pd. See J. Chem. Eng. of Japan 35(3) (2002) 255.